WITH THE CHAIN ALONE, THE COMPASS, THE TRANSIT, ILLUSTRATED BY FOUR HUNDRED ENGRAVINGS, BY W. M. GILLESPIE, LL. D., CIV. ENG., PROFESSOR OF CIVIL ENGINEERING IN UNION COLLEGE. EIGHTH EDITION. NEW YORK: D. APPLETON & COMPANY, 549 & 551 BROADWAY. LONDON: 16 LITTLE BRITAIN. 1873. ! 65 に73 Entered, according to the Act of Congress, in the year 1855, by In the Clerk's Office of the District Court of the United States for the Southern 11400 PREFACE. LAND-SURVEYING is perhaps the oldest of the mathematical arts. Indeed, Geometry itself, as its name-"Land-measuring"-implies, is said to have arisen from the efforts of the Egyptian sages to recover and to fix the land-marks annually swept away by the inundations of the Nile. The art is also one of the most important at the present day, as determining the title to land, the foundation of the whole wealth of the world. It is besides one of the most useful as a study, from its striking exemplifications of the practical bearings of abstract mathematics. But, strangely enough, Surveying has never yet been reduced to a systematic and symmetric whole. To effect this, by basing the art on a few simple principles and tracing them out into their complicated ramifications and varied applications (which extend from the measurement of "a mowing lot" to that of the Heavens), has been the earnest endeavor of thepresent writer. The work, in its inception, grew out of the author's own needs. Teaching Surveying, as preliminary to a course of Civil Engineering, he found none of the books in use (though very excellent in many respects) suited to his purpose. He was therefore compelled to teach the subject by a combination of familiar lectures on its principles and exemplifications of its practice. His notes continually swelling in bulk, gradually became systematized in nearly their present form, and in 1851 he printed a synopsis of them for the use of his classes. His system has thus been fully tested, and the present volume is the result. |